Hello, I am trying to estimate a 2-stage selection Model where the first probit stage is whether the customer bought (0/1) and the second stage is given that the customer bought, how much did they spend (revenue). However, in my data, customers are nested within customer service agents and customer service agents are nested within countries, thereby requiring an mixed model or HLM format. Do you know of code that would accommodate this? I found code for a Heckit model and one more HLM models but not one that combines both. Any help would be greatly appreciated. Thanks in advance. Nita [[alternative HTML version deleted]]